What is an acronym? Well, let’s begin with a different question. What do the following have in common: DVD, UN, CND, BBC, GSOH, and TV? If you answered ‘they’re all acronyms’, then read on. For it’s necessary to make a fine but important distinction between bona fide acronyms and other kinds of abbreviation.
Strictly speaking, an acronym is a word which has been formed from the initial letters of other words. The key word here is ‘word’. So, NATO is an acronym because the four letters are pronounced to form a word (pronounced as ‘Nay-Tow’) rather than being pronounced as separate letters (i.e. N-A-T-O). NATO is thus an acronym formed from the initials of the phrase North Atlantic Treaty Organisation. Similarly, the word nimby – used to refer to someone who is all in favour of something, as long as it doesn’t happen on their doorstep – is an acronym formed from the phrase ‘Not In My Back Yard’. The initial letters of the phrase are taken to form N-I-M-B-Y. But this is then pronounced, not as individual letters, but as any word would be, i.e. ‘Nim-Bee’.
An acronym, then, is pronounced as a word; DVD (Digital Versatile Disc), BBC (British Broadcasting Corporation), and so on are not acronyms because they are pronounced not as words but as individual letters: D-V-D, and so on. Such formations are known as initialisms rather than acronyms, and are considerably more common. Initialisms only tend to become acronyms if the arrangement of letters can be voiced like a word, so it helps to have some vowels in there: NATO sounds like it could be a word, but DVD does not.
It’s sometimes claimed that the term acronym should include initialisms, and certainly, when the word was first used, this was the case. Here, the Oxford English Dictionary provides some much-needed illumination. The OED offers two ‘senses’ or meanings for ‘acronym’: the first is defined as ‘a group of initial letters used as an abbreviation for a name or expression, each letter or part being pronounced separately; an initialism (such as ATM, TLS)’ and is attested from 1940 (its origins were in the US). This definition of ‘acronym’ embraces or includes the sense of ‘initialism’, as the examples of ATM and TLS show. The second sense or meaning the OED offers is defined as ‘a word formed from the initial letters of other words or (occasionally) from the initial parts of syllables taken from other words, the whole being pronounced as a single word (such as NATO, RADA).’ This sense of ‘acronym’ is attested from 1943, just three years after the first, but the meaning has already narrowed to refer specifically to words formed from initial letters, and does not include initialisms, as the examples of NATO and RADA demonstrate. Even under its definition of sense 1, the OED (whose short-form name is an initialism, of course, as it’s pronounced O-E-D rather than ‘Oh-Ed’) states: ‘In the O.E.D. the term initialism is used for this phenomenon.’ So it’s something of a misconception to say that, because the word initially (and very briefly) had a broader meaning, that the terms acronym and initialism should remain interchangeable. It’s clear that they very quickly separated and ‘acronym’ came to be applied narrowly to words rather than any set of initials.
If we insist on a distinction between acronyms and initialisms, this means that PIN (‘personal identification number’) is a bona fide acronym while the thing you key your PIN into, an ATM (‘automated teller machine’) is an initialism. Curiously, in both examples, the terms’ origins in initials are swiftly forgotten by many users, who refer to keying their PIN number (so ‘personal identification number number’) into the ATM machine (‘automated teller machine machine’).
The word ‘acronym’ is derived from ancient Greek words meaning ‘end’ or ‘topmost’ and ‘name’, because one takes the first or ‘topmost’ letter in each word and forms a ‘name’ with it. Other famous examples of acronyms include radar (from RAdio Detection And Ranging), scuba (‘Self-Contained Underwater Breathing Apparatus’), laser (‘Light Amplification by Stimulated Emission of Radiation’), and, more recently, gif (‘Graphics Interchange Format’; curiously, the creator of this format pronounced the acronym as ‘jif’, in a deliberate echo of an American brand of peanut butter, but it was the pronunciation of ‘gif’, with a hard g, which won out among the general populace).
Curiously, as the OED dates for earliest citations of the word in its two senses (1940 and 1943) attest, acronyms are a relatively recent phenomenon. They really got a leg up during the Second World War: many serving officers would write home to their wives and sweethearts and employ acronyms that expressed how they felt, e.g. SWALK (‘sealed with a loving kiss’), ITALY (‘I trust and love you’), BOLTOP (‘better on lips than on paper’, said of a kiss at the end of a letter), or, for the saucier love-letter writer, BURMA (‘be upstairs ready my angel’).
This hasn’t stopped people from claiming that much older words are acronyms, formed from now forgotten phrases. This is where the fact that acronyms are words rather than a mere string of initials becomes highly relevant: it means that some etymology-hunters have seen a word with an unexplained origin and tried to come up with a plausible acronym for it. The word ‘posh’ is one example, which many people still believe comes from the nineteenth-century phrase ‘Port Out, Starboard Home’, which was said to be printed on the tickets of those passengers on P&O ships who had a berth on the more favourable side of the ship (i.e. the port or left side on the voyage out to India, and the starboard or right side on the journey home). The logic is that those who had one of these better berths on the ship had more money, and were therefore probably upper-class or ‘posh’. There’s one major problem with this theory, which is that P&O never printed such a thing on their tickets. Indeed, the origins of the word ‘posh’ aren’t known for sure, but we can discount the acronym theory pretty decisively.
Other attempts to explain the etymology of a particular word via acronyms have similarly proved to be false: ‘chav’ doesn’t come from ‘council housed and violent’, and ‘golf’ isn’t from ‘gentlemen only; ladies forbidden’. Such folk etymologies have a rather splendid name: backronyms, from a blend of ‘back’ and ‘acronyms’, on the basis that one is trying to go back and find an explanation for how the word came about via an acronym.